1. Field of the Invention
The present invention relates to an information processing device having an object to be cooled, which is a heat-generating body, and a cooling unit for radiating the heat transferred from the object.
2. Description of Related Art
Information processing devices provided with a integrated circuit such as a CPU (Central Processing Unit) are conventionally known. Such information processing device includes a personal computer (PC) and a disc reproducing device that reproduces image and sound information recorded in a recording medium such as an optical disc including CD (Compact Disc), DVD (Digital Versatile Disc), BD (Blu-ray Disc: registered trade name) and the like or stored in a memory medium such as a semiconductor memory card and an HDD (Hard Disk Drive).
Since the integrated circuits used in the information processing device (especially, a CPU) generate large amount of heat and are weak against heat, the integrated circuits have to be efficiently cooled in order to ensure stable operation of the information processing device. Recent size-reduction of electronics contributes accumulation of heat generated by a heat-generating body such as the integrated circuits within the electronics. Also, the amount of the heat generated increases in accordance with improvement in processing speed of the integrated circuits. Therefore, there is growing necessity for efficient cooling of the integrated circuits.
In order to cool the integrated circuits, a structure has been developed, where a heat sink is provided to cover a CPU and a chipset that are juxtaposed on a circuit board. The heat of the CPU and the chipset transferred to the heat sink is cooled by a fan (see, for instance, Document 1: JP2000-20172A).
In the cooling mechanism shown in the Document 1, the chipset that generates relatively small heat is cooled by internal air inside the information processing device (PC). The CPU that generates relatively large amount of heat is cooled by external air introduced from the outside of the information processing device. The above arrangement allows cooling of the CPU with the use of external air that is cooler than the internal air.
The heat sink and the fan of the cooling mechanism shown in the Document 1 are fixed by a screw and the like on a side of the circuit board on which the integrated circuits such as the CPU and the chipset are mounted. In the above mechanism, however, the tightening force of the screw screwed into the board to secure the heat sink and the fan may deform the circuit board. The disadvantage is prominently recognized in securing a large-size heat sink and fan on the circuit board, where greater tightening force has to be applied.
Further, since the heat sink is not in contact with the CPU (object to be cooled) in the cooling mechanism shown in the Document 1, the heat is not directly transferred from the CPU to the heat sink. Thus, since the heat generated by the CPU is dissipated only via a casing of the CPU, only a small heat-radiation area can be obtained, which results in poor cooling efficiency even when the cooling air is sent from the fan.